1. Field of the Invention
The present invention relates to a metal ink that includes a metal nano particle and an organic solvent, and a method for producing a metal wire by using the metal ink.
This application claims priority from Korean Patent Application No. 10-2007-0133670 filed on Dec. 18, 2007 in the KIPO, the disclosure of which is incorporated herein by reference in its entirety.
2. Description of the Related Art
Recently, in various fields of electronic part industries, an ink-jet printing process comes into the spotlight. The ink-jet printing process is a technology that is generally used in a document printing, but applied to various fields of electronic part development processes such as LCD color filters, RFID tags and the like, or the application to those fields is examined.
The printing of the conductive patterns such as RFID tags, PCB substrates, electrodes for PDP is carried out by spraying a conductive metal ink for ink-jet printing on a substrate.
The metal particle that is used in a general conductive metal ink for ink-jet printing is a single metal or an alloy of two or more metals, and single dispersion particles having the nano size are used so that firing is easily performed at low temperatures and the dispersion is well performed.
In order to synthesize the mono dispersed metal particle having the nanosize, a polyol process is mostly used. In the case of the metal particles that are synthesized by using the polyol process, in order to prevent the oxidation on the surface and to increase the dispersibility, a dispersing agent such as PVP (poly vinyl pyrrolidone) is capped. Accordingly, the conductive metal inks have largely different dispersibilities according to the characteristics of the solvent that is used in conjunction with the dispersing agent.
Korean Unexamined Patent Application Publication No. 2006-0043182 discloses that water and an watersoluble organic solvent are mixed with each other to prepare metal ink because of the dispersion of the metal ink and ease of the production of the metal ink. However, since water is a solvent having a very high surface tension, an operation for controlling the surface tension in order to make spraying possible is required. In addition, if the metal nano particles are contacted with water, since the oxidation occurs, there is a high risk in which the conductivity of the metal ink is reduced.